Harry Potter, Hermione Granger and Ron Weasley, along with Neville Longbottom, first encountered Fluffy when Draco Malfoy challenged Harry to a duel, which he accepted. When Hermione tried to stop Harry and Ron from sneaking out later that night, she found herself locked out of the Gryffindor Tower, as the Fat Lady had gone for an evening stroll, and ended up going along with them. Neville Longbottom, who had forgotten the password to the common room and was sleeping on the floor outside, joined them as well. When they arrived at the Trophy Room, the intended site of the duel, Malfoy was nowhere to be found. To avoid being caught by Argus Filch, they ran away and end up in the forbidden area on the third floor, staring at a massive three-headed dog. Despite being furious about having broken countless school rules, Hermione had noticed that the dog was standing on a trap door, and clearly guarding something. They later deduced, from hints about Nicolas Flamel dropped unintentionally by Hagrid, that this "something" was the Philosopher's Stone.

Later that year, Hagrid happily told the trio that he had a won a dragon egg in a card game at the Hog's Head. Thinking that it was too much of a coincidence that, as Hagrid had always dreamed of owning a dragon, someone just happened to show up at the local pub with a dragon egg, the trio questioned Hagrid about the supposed Dragon dealer. Upon finding out that Hagrid had never even seen the man's face, as he wore a hood, but had drunkenly told him how to get past Fluffy, they came to the horrifying conclusion that the hooded man must have been Severus Snape. As that meant the stone was no longer safe, they decided to go after Snape themselves, and Harry brought along the Flute that Hagrid had given him for Christmas, to use in lulling Fluffy to sleep. Arriving at the room, they noticed an enchanted Harp at a sleeping Fluffy's feet, and believed that Professor Snape was already on his way to retrieving the stone. Fluffy soon awoke, as the enchantment on the harp wore off, and it stopped playing. As Harry played the flute, which almost immediately put Fluffy back to sleep, Ron crept over to the trap door and opened it, but was unable to see anything below. Hermione took over playing the flute, while Harry jumped in first, followed by Ron. After they called up to Hermione that it was safe, she stopped playing and jumped down the trap door just in time, as Fluffy woke up as soon as the music stopped.

After Fluffy's duties were done, and the Stone was destroyed, Hagrid set Fluffy free in the Forbidden Forest. Presumably, he is still there, as it is never stated that he was removed from the forest when Voldemort was there.[1]

Personality and traits

Fluffy was generally vicious, quite fierce, and extremely strong, though he possibly acted somewhat more docile around certain people, like Rubeus Hagrid, who was able to get Fluffy into the third floor corridor. Another way to calm Fluffy was to play music, which made him fall asleep. Three-headed dogs are very rare creatures, and it is unknown if, like the Runespoor, each head serves a different purpose.

Behind the scenes

In the film adaptation Neville was not present when the trio first met Fluffy.

In the book Quirrell and the trio use different musical instruments to put Fluffy to sleep, a harp and a flute. In the film adaptation the harp is still playing when they enter the room and only stops just before they jump down into the trap door just in the nick of time. In LEGO Harry Potter: Years 1-4 the harp is broken when they first enter the room and they have to distract Fluffy with a Rubber duck so that they can fix the harp.

Three-headed dogs are prominent in Greek and Roman mythology and are also known as hellhounds, the chief of all being Cerberus, Guardian to the Underworld. It is odd that the film adaptation would rather have had Hagrid purchase Fluffy from an Irish as opposed to Greek man, as Cerberus played a major role in Greek mythology.

A single-headed version would also bear a considerable resemblance to Garm, the Norse blood-stained watchdog of Hel's gate.

In Harry Potter and the Deathly Hallows Fluffy may have participated in the Battle of Hogwarts, as he was set free in the Forbidden Forest, and permanent residents who lived in the forest fought in the battle[citation needed]